Because signs may first appear with puberty, polycystic ovary syndrome (PCOS) is generally considered a disease of adolescence or adults, but there is increasing evidence that its origins may be earlier and that early signs (PCO, insulin resistance) may be detectable in childhood. However, there have been no studies in prepubertal and early pubertal girls, at about ages 5-8 years, that have had examined the relationships among ovarian morphology, size, central adiposity and biomarkers of insulin resistance, and it therefore remains to be established whether ovarian enlargement and/or the appearance of PCO precedes, is subsequent to, or is unrelated to the development of insulin resistance, central adiposity (visceral fat), and dyslipidemia in prepubertal and early pubertal girls. This project will augment the Growing Up Female (GUF) study, being conducted through the University of Cincinnati (Children?s Hospital Medical Center [CCHMC]) by a research team headed by Dr. Frank M. Biro. The GUF is planned to be a cohort study of approximately 450-500 elementary school white and African-American girls, ages 6-7, followed longitudinally for five years with semi-annual in-school examinations that are scheduled to begin in September of 2004. The girls will have semi-annual physical exams (examination rounds) to determine body size, central adiposity, and pubertal status and for the collection of fasting blood specimens. This project will add a component to develop methods for assessing clinical signs on abdominal ultrasound and biomarkers for the study of the early childhood origins of PCOS. On the sample of approximately 500 6-7 year old girls recruited and measured in the first round of data collection (September-November, 2004), we will measure biomarkers of insulin resistance (fasting serum insulin, plasma glucose, and lipids) and examine the cross-sectional relationships among adiposity and regional fat distribution, as determined by anthropometry, and indicators of insulin resistance. In the second year of the GUF study, for a subsample of 200 prepubertal or early pubertal girls, ages 7-8 years, we will measure factors known to be associated with the later development of PCOS on abdominal ultrasound (PCO, ovarian volume and morphology, visceral fat) and biomarkers (fasting serum insulin, plasma glucose, and lipids) and to examine the cross-sectional relationships among ovarian size and morphology, adiposity and regional fat distribution, and indicators of insulin resistance. The findings from this project will either serve as a basis or as a pilot to develop a definitive study on the prepubertal and early pubertal biomarkers and clinical signs of PCOS.